A Case of Extensive Thromboembolism as a First Presentation of a Pheochromocytoma: Pathophysiologic Insights and Strategic Surgical Intervention

Pheochromocytomas are rare and often underdiagnosed neuroendocrine tumors characterized by excessive catecholamine production, typically presenting in the fourth to fifth decades of life. While the classic presentation includes labile hypertension and a triad of headaches, palpitations, and sweating, thromboembolism as an initial manifestation of pheochromocytoma is exceedingly rare. In this case report, a 78-year-old male patient with cardiovascular risk factors initially presented with a clinical picture consistent with acute coronary syndrome. However, further clinical workup revealed extensive bilateral pulmonary emboli and an incidental adrenal mass. Subsequent biochemical testing and metaiodobenzylguanidine (MIBG) scintigraphy confirmed the diagnosis of pheochromocytoma. A concurrent thromboembolic workup revealed an underlying protein S deficiency. The patient was managed medically with alpha- and beta-adrenergic blockade. Following hemodynamic stabilization, the patient underwent successful laparoscopic adrenalectomy. Postoperative follow-up demonstrated complete resolution of symptoms and near normalization of biochemical markers. In this report, the pathogenesis of thromboembolism in pheochromocytoma is discussed, highlighting both the clinical features and the sophisticated surgical approach to this complex disorder.